[PATCH] mmc: dw_mmc: rockchip: add support MMC_CAP_RUNTIME_RESUME capability
From: dianders@chromium.org (Doug Anderson)
Date: 2015-02-19 19:16:51
Also in:
linux-mmc, lkml
Addy, On Thu, Feb 12, 2015 at 11:22 PM, Addy Ke [off-list ref] wrote:
quoted hunk ↗ jump to hunk
To support HS200 and UHS mode, mmc core will call init_card() to execute tuning: - sdio: init_card can be executed at runtime resume. - sd and mmc: init_card can be executed at resume or runtime resume, which depends on MMC_CAP_RUNTIME_RESUME capability. On rk3288 SoC, host will get DRTO interrupt when host send command to read tuning data. This will spend more than 111ms: drto_ms = drto_clks * 1000 / bus_hz = 111ms. And the total tuning time will be more than 400ms. So we should add MMC_CAP_RUNTIME_RESUME capability to execute tuning at runtime resume. Only if we do so, can we pass resume test. Signed-off-by: Addy Ke <redacted> --- drivers/mmc/host/dw_mmc-rockchip.c | 8 ++++++++ 1 file changed, 8 insertions(+)diff --git a/drivers/mmc/host/dw_mmc-rockchip.c b/drivers/mmc/host/dw_mmc-rockchip.c index e2a726a..e5f57b5 100644 --- a/drivers/mmc/host/dw_mmc-rockchip.c +++ b/drivers/mmc/host/dw_mmc-rockchip.c@@ -76,12 +76,20 @@ static int dw_mci_rockchip_init(struct dw_mci *host) return 0; } +/* Common capabilities of RK3288 SoC */ +static unsigned long dw_mci_rk3288_dwmmc_caps[4] = { + MMC_CAP_RUNTIME_RESUME, /* emmc */ + MMC_CAP_RUNTIME_RESUME, /* sdmmc */ + 0, /* sdio0 */ + 0, /* sdio1 */
Why not add it for all 4 slots? On the board you're working on the "SDIO" slot always has an SDIO module in it, but there is nothing restricting someone from actually adding a physical slot here and plugging in a real SD card. In that case you'd want MMC_CAP_RUNTIME_RESUME there too, right? With that addition you could add my Reviewed-by. Other than that this seems OK to me. I'd imagine that eventually we could get tuning to be a bit faster, maybe by tweaking timeouts. Specifically the SD Card Spec that I see (in the "Tuning Command" part of the Physical Layer Specification) talks about being able to complete tuning in <= 150ms. ...but even then speeding up resume time by 2 * 150ms = 300ms seems like a good thing. -Doug